Version of MessagePumpForUI optimized for GPU process

base/message_loop/message_pump_win.h

Index: base/message_loop/message_pump_win.h
diff --git a/base/message_loop/message_pump_win.h b/base/message_loop/message_pump_win.h
index 6f4b699cefdfce5a3fac2249d6ebbcc2bf4c5bed..69291dc78a83370634370e78612318d70fda47ce 100644
--- a/base/message_loop/message_pump_win.h
+++ b/base/message_loop/message_pump_win.h
@@ -22,7 +22,7 @@ namespace base {
 // controlling the lifetime of the message pump.
 class BASE_EXPORT MessagePumpWin : public MessagePump {
  public:
-  MessagePumpWin() : have_work_(0), state_(NULL) {}
+  MessagePumpWin() : work_state_(READY), state_(NULL) {}
 
   // MessagePump methods:
   void Run(Delegate* delegate) override;
@@ -39,22 +39,69 @@ class BASE_EXPORT MessagePumpWin : public MessagePump {
     int run_depth;
   };
 
+  // State used with work_state_ variable.
+  enum WorkState {
+    READY = 0,      // Ready to accept new work.
+    HAVE_WORK = 1,  // New work has been signalled.
+    WORKING = 2     // Handling the work.
+  };
+
   virtual void DoRunLoop() = 0;
   int GetCurrentDelay() const;
 
   // The time at which delayed work should run.
   TimeTicks delayed_work_time_;
 
-  // A boolean value used to indicate if there is a kMsgDoWork message pending
+  // A value used to indicate if there is a kMsgDoWork message pending
   // in the Windows Message queue.  There is at most one such message, and it
   // can drive execution of tasks when a native message pump is running.
-  LONG have_work_;
+  LONG work_state_;
 
   // State for the current invocation of Run.
   RunState* state_;
 };
 
 //-----------------------------------------------------------------------------
+// MessagePumpForUIBase serves as a base class for for specialized versions of
+// MessagePump instantiated with TYPE_UI. It provides basic functionality for
+// creating a hidden window with a message queue and handling window messages,
+// including the special kMsgHaveWork message that indicates the scheduled work,
+// handling timers, etc.
+//
+class BASE_EXPORT MessagePumpForUIBase : public MessagePumpWin {
+ public:
+  // The application-defined code passed to the hook procedure.
+  static const int kMessageFilterCode = 0x5001;
+
+  MessagePumpForUIBase();
+  ~MessagePumpForUIBase() override;
+
+  // MessagePump methods:
+  void ScheduleWork() override;
+
+ protected:
+  virtual void HandleWorkMessage() = 0;
+  virtual void HandleTimerMessage() = 0;
+
+  bool IsWorkMessage(const MSG& msg) const;
+  void SetTimer(int delay_msec);
+  void KillTimer();
+
+ private:
+  static LRESULT CALLBACK WndProcThunk(HWND window_handle,
+                                       UINT message,
+                                       WPARAM wparam,
+                                       LPARAM lparam);
+  void InitMessageWnd();
+
+  // Atom representing the registered window class.
+  ATOM atom_;
+
+  // A hidden message-only window.
+  HWND message_hwnd_;
+};
+
+//-----------------------------------------------------------------------------
 // MessagePumpForUI extends MessagePumpWin with methods that are particular to a
 // MessageLoop instantiated with TYPE_UI.
 //
@@ -102,38 +149,53 @@ class BASE_EXPORT MessagePumpWin : public MessagePump {
 // an excellent choice.  It is also helpful that the starter messages that are
 // placed in the queue when new task arrive also awakens DoRunLoop.
 //
-class BASE_EXPORT MessagePumpForUI : public MessagePumpWin {
+class BASE_EXPORT MessagePumpForUI : public MessagePumpForUIBase {
  public:
-  // The application-defined code passed to the hook procedure.
-  static const int kMessageFilterCode = 0x5001;
-
   MessagePumpForUI();
   ~MessagePumpForUI() override;
 
+ private:
   // MessagePump methods:
-  void ScheduleWork() override;
+  void DoRunLoop() override;
   void ScheduleDelayedWork(const TimeTicks& delayed_work_time) override;
 
- private:
-  static LRESULT CALLBACK WndProcThunk(HWND window_handle,
-                                       UINT message,
-                                       WPARAM wparam,
-                                       LPARAM lparam);
-  void DoRunLoop() override;
-  void InitMessageWnd();
-  void WaitForWork();
-  void HandleWorkMessage();
-  void HandleTimerMessage();
-  void RescheduleTimer();
+  void HandleWorkMessage() override;
+  void HandleTimerMessage() override;
+
   bool ProcessNextWindowsMessage();
+  void WaitForWork();
+
   bool ProcessMessageHelper(const MSG& msg);
   bool ProcessPumpReplacementMessage();
+  void RescheduleTimer();
+};
 
-  // Atom representing the registered window class.
-  ATOM atom_;
+//-----------------------------------------------------------------------------
+// MessagePumpForGpu is a simplified version of MessagePumpForUI that is
+// optimized for the GPU process. Unlike MessagePumpForUI it doesn't handle a
+// situation where a native message pump might be used by modal dialogs and
+// message boxes. That allows to skip some system calls like setting and killing
+// timers, getting status of the message queue, etc.
 
-  // A hidden message-only window.
-  HWND message_hwnd_;
+class BASE_EXPORT MessagePumpForGpu : public MessagePumpForUIBase {
+ public:
+  MessagePumpForGpu();
+  ~MessagePumpForGpu() override;
+
+  // Factory methods.
+  static void InitFactory();
+  static scoped_ptr<MessagePump> CreateMessagePumpForGpu();
+
+ private:
+  // MessagePump methods:
+  void DoRunLoop() override;
+  void ScheduleDelayedWork(const TimeTicks& delayed_work_time) override;
+
+  void HandleWorkMessage() override;
+  void HandleTimerMessage() override;
+
+  void ProcessWindowsMessages();
+  void WaitForWork();
 };
 
 //-----------------------------------------------------------------------------